/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.qihoo.qsql.org.apache.calcite.util.graph;

import java.util.Set;

/**
 * Detects cycles in directed graphs.
 *
 * @param <V> Vertex type
 * @param <E> Edge type
 */
public class CycleDetector<V, E extends DefaultEdge> {
  private final DirectedGraph<V, E> graph;

  public CycleDetector(DirectedGraph<V, E> graph) {
    this.graph = graph;
  }

  public Set<V> findCycles() {
    return new TopologicalOrderIterator<>(graph).findCycles();
  }
}

// End CycleDetector.java
